1. Technical Field
The present subject matter relates to reinforcement systems. Particularly, the present subject matter relates to three-dimensional aggregate reinforcement systems and methods.
2. Description of Related Art
Pavements that are used to facilitate vehicle traffic typically include a surface layer of asphaltic concrete or Portland cement concrete overlying a sub-layer of base course aggregate overlying natural or stabilized subgrade. The thickness of the layers of the pavement materials can depend upon the desired design life, the applied vehicle loading, and the stiffness of each of the components. For a given traffic loading condition, thinner layers of the materials with stiffer material properties may be used to replace thicker layers of materials with softer properties. In conventional construction, stiffness of the pavement sub-layers may sometimes be enhanced by adding binding or chemically modifying materials such as cement, lime, fly ash, or combinations of these materials, by incorporating layers of geosynthetic materials such as geogrids or geotextiles within the pavement layers, and by replacing the weak subgrade materials with a thick aggregate layer.
Geogrids have been developed to reinforce soils, pavement systems, and similar materials. They are currently used in some pavement sections to stabilize the subgrade materials and to enhance the performance of base course materials. Geogrids are commonly made of polymer materials, such as polyester, polyethylene, or polypropylene. A particular type of geogrrid is a biaxial (BX) polymeric geogrid. The term “biaxial” refers to the provision of two sets of continuous ribs through each node (i.e., connection points at rib intersections). Triaxial geogrids, which have three sets of continuous ribs through each node and provide increased nodal and system stability, are also used. Although current geogrids enhance the stiffness of the aggregate layer, it is desired to provide systems having a greater amount of layer composite stiffness. More generally, there is a continuing need for improved reinforcement systems and techniques.